From: Jens Axboe <axboe@xxxxxxxxx>
commit f58680085478dd292435727210122960d38e8014 upstream.
If CONFIG_PREEMPT_NONE is set and the task_work chains are long, we
could be running into issues blocking others for too long. Add a
reschedule check in handle_tw_list(), and flush the ctx if we need to
reschedule.
Cc: stable@xxxxxxxxxxxxxxx # 5.10+
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
io_uring/io_uring.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -1030,10 +1030,16 @@ static unsigned int handle_tw_list(struc
/* if not contended, grab and improve batching */
*locked = mutex_trylock(&(*ctx)->uring_lock);
percpu_ref_get(&(*ctx)->refs);
- }
+ } else if (!*locked)
+ *locked = mutex_trylock(&(*ctx)->uring_lock);
req->io_task_work.func(req, locked);
node = next;
count++;
+ if (unlikely(need_resched())) {
+ ctx_flush_and_put(*ctx, locked);
+ *ctx = NULL;
+ cond_resched();
+ }
}
return count;
